Valve system of surgical cassette manifold, system, and methods thereof

ABSTRACT

A surgical system includes a replaceable surgical cassette that is configured to be received by a surgical console, the surgical cassette permitting fluid flow through the cassette, the surgical system controlling the flow of fluid through the cassette via one or more flexible valves actuated by one or more actuation plungers located on the surgical console. The one or more flexible valves of the surgical cassette and the one or more actuation plungers of the surgical console include a positioning feature configured to assist with positioning the one or more actuation plungers to apply uniform and symmetric pressure to the one or more valves during actuation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation-in-partapplication of U.S. application Ser. No. 14/686,582 filed on Apr. 14,2015, which claims priority to and is a continuation-in-part of U.S.application Ser. No. 13/776,988 filed on Feb. 26, 2013, which claimspriority to U.S. provisional application No. 61/612,307 filed on Mar.17, 2012, the contents of each are hereby incorporated by reference intheir entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention is generally related to methods, devices, andsystems for controlling surgical fluid flows, particularly duringtreatment of an eye. More particularly, the present invention generallyrelates to methods, devices and systems associated with a valve systemof a removable cassette for controlling surgical fluid flows.

BACKGROUND OF THE INVENTION

The optical elements of the eye include both a cornea (at the front ofthe eye) and a lens within the eye. The lens and cornea work together tofocus light onto the retina at the back of the eye. The lens alsochanges in shape, adjusting the focus of the eye to vary between viewingnear objects and far objects. The lens is found just behind the pupil,and within a capsular bag. This capsular bag is a thin, relativelydelicate structure which separates the eye into anterior and posteriorchambers.

With age, clouding of the lens or cataracts are fairly common. Cataractsmay form in the hard central nucleus of the lens, in the softerperipheral cortical portion of the lens, or at the back of the lens nearthe capsular bag.

Cataracts can be treated by the replacement of the cloudy lens with anartificial lens. Phacoemulsification systems often use ultrasound energyto fragment the lens and aspirate the lens material from within thecapsular bag. This may allow the capsular bag to be used for positioningof the artificial lens, and maintains the separation between theanterior portion of the eye and the vitreous humour in the posteriorchamber of the eye.

During cataract surgery and other therapies of the eye, accurate controlover the volume of fluid within the eye is highly beneficial. Forexample, while ultrasound energy breaks up the lens and allows it to bedrawn into a treatment probe with an aspiration flow, a correspondingirrigation flow may be introduced into the eye so that the total volumeof fluid in the eye does not change excessively. If the total volume offluid in the eye is allowed to get too low at any time during theprocedure, the eye may collapse and cause significant tissue damage.Similarly, excessive pressure within the eye may strain and injuretissues of the eye.

While a variety of specific fluid transport mechanisms have been used inphacoemulsification and other treatment systems for the eyes, aspirationflow systems can generally be classified in two categories: 1)volumetric-based aspiration flow systems using positive displacementpumps; and 2) vacuum-based aspiration systems using a vacuum source,typically applied to the aspiration flow through an air-liquidinterface. These two categories of aspiration flow systems each haveunique characteristics that render one more suitable for some proceduresthan the other, and vice versa.

Among positive displacement aspiration systems, peristaltic pumps (whichuse rotating rollers that press against a flexible tubing to induceflow) are commonly employed. Such pumps provide accurate control overthe flow volume. The pressure of the flow, however, is less accuratelycontrolled and the variations in vacuum may result in the feel ortraction of the handpiece varying during a procedure. Peristaltic andother displacement pump systems may also be somewhat slow.

Vacuum-based aspiration systems provide accurate control over the fluidpressure within the eye, particularly when combined with gravity-fedirrigation systems. While vacuum-based systems can result in excessivefluid flows in some circumstances, they provide advantages, for example,when removing a relatively large quantity of the viscous vitreous humourfrom the posterior chamber of the eye. However, Venturi pumps and othervacuum-based aspiration flow systems are subject to pressure surgesduring occlusion of the treatment probe, and such pressure surges maydecrease the surgeon's control over the eye treatment procedure.

Different tissues may be aspirated from the anterior chamber of the eyewith the two different types of aspiration flow. For example,vacuum-induced aspiration flow may quickly aspirate tissues at asignificant distance from a delicate structure of the eye (such as thecapsular bag), while tissues that are closer to the capsular bag areaspirated more methodically using displacement-induced orpositive-displacement flows.

Conventionally, fluid aspiration systems include a console and a fluidiccassette mounted on the console. The fluidic cassette is typicallychanged for each patient and cooperates with the console to providefluid aspiration. Generally, a single type of cassette is used by aparticular console, regardless of whether the procedure will requirepositive displacement aspiration, vacuum-based aspiration, or both.Examples of cassettes currently used in the marketplace may be found inU.S. Pat. No. 8,070,712, U.S. Published Application 2008011431, and U.S.Published Application 20080114291, the contents of each are herewithincorporated by reference in their entirety as if set forth herein. U.S.applications Ser. Nos. 14/686,582 and 13/776, 988, which are herebyincorporated by reference in their entirety as if set forth herein,provide examples of cassettes.

A fluidic cassette may include means for controlling fluid flow throughthe cassette. In various embodiments, a fluidic cassette may include agasket or flexible membrane located within the cassette that isconfigured to direct fluid flow in a predetermined flow path through thecassette. The gasket may be surrounded by front and back plates thatform the body of the cassette, and the gasket may include one or morevalves or a sensor that are accessible through the back plate. Thesurgical cassette may further include one or more tube retainersconfigured and dimensioned to guide a portion of either an irrigation oraspiration tube into a desired shape. The desired shape may be capableof being used with a peristaltic pump to pump fluid through the pathwaysformed by the gasket.

A gasket of a fluidic cassette may have a body, wherein the body isdeformable and has a front surface and a back surface. The front surfacemay have one or more raised contours that create one or more channelsthat are configured and dimensioned to control fluid flow through one ormore corresponding channels of a surgical cassette. The back surface mayhave one or more elevated portions that correspond to the one or morechannels of the front surface and act as a valve. The gasket may alsohave a deformable membrane having an annular surface capable of couplingwith a transducer of a surgical console. The console may include one ormore solenoid devices that engage with the back surface of the gasketthrough the back plate of the cassette, thereby operating or controllingthe valve of the gasket to control fluid flow in the flow pathway.

In light of the above, it would be advantageous to provide improveddevices, systems, and methods for eye surgery, and more particularly forthe control of fluid flow through a fluidic cassette during eye surgery.

SUMMARY OF THE INVENTION

The present invention provides a surgical cassette manifold, having afront housing, a rear housing, and a gasket, wherein the front housingcomprises one or more molded fluid channels and one or more sealchannels, herein the gasket is coupled with the rear housing and atleast a portion of the gasket is located between the front housing andthe rear housing, and wherein the gasket has one or more seal lipsconfigured and dimensioned to couple with the one or more seal channelsto form one or more fluid flow channels through the cassette. The gasketcomprises one or more valves controllable through the rear housing, thevalves configured to extend into the one or more fluid flow channels toreduce or block fluid flow through the flow channels.

The present invention provides a surgical cassette manifold configuredto be coupled to a surgical console, the cassette manifold having afront housing, a rear housing, and a flexible gasket, wherein the gasketcomprises one or more flexible flow restriction valves that reduce orblock fluid flow through flow channels in the cassette, the flowrestriction valves positioned along either a first flow path ofirrigation fluid flowing through the cassette to a surgical handpiece ora second flow path of aspirated fluid from the surgical handpieceflowing through the cassette, or both. The flow restriction valves areactuated to reduce or block fluid flow through the first or second flowpaths via one or more actuation plungers located on the surgicalconsole. In various embodiments, the plungers may be actuated by asolenoid or other similar means to apply pressure to the flexible valvesto deform the flexible valves into the flow paths.

The present invention provides a surgical cassette manifold configuredto be coupled to a surgical console, the cassette manifold including aflexible gasket comprising one or more valves that reduce or block fluidflow through the surgical cassette, wherein the one or move valves arepositioned adjacent a first flow path of fluid flowing into a surgicalhandpiece from the cassette and a second flow path of fluid flowingthrough the cassette that has been aspirated from the surgicalhandpiece. The one or more valves are actuated by an actuation plungerof the surgical console, which may be electronically controlled by acontroller of the console. In various embodiments, the plungers may beactuated by a solenoid or other similar means to apply pressure to theflexible valves to deform the flexible valves into the flow paths.

In illustrative embodiments, one or more flexible valves of a surgicalcassette and one or more actuation plungers of a surgical consoleinclude a positioning feature configured to assist with positioning theone or more actuation plungers to apply uniform and symmetric pressureto the one or more valves. The positioning feature includes at least twofeatures: (i) a locking recess on a back surface of the one or morevalves, the locking recess formed between two spaced-apart teeth orprotrusions that extend axially away from (and are generallyperpendicular to) the valve surface; and (ii) a blade tooth that extendsaxially away from an end surface of the plunger and is configured to bereceived with the locking recess to engage the valve. The positioningfeature ensures the plunger is properly aligned with the flexible valveas the valve is deformed inward under pressure from the plunger.

In illustrative embodiments, a positioning feature of the surgicalcassette and a surgical console may include i) a locking recess on aback surface of the one or more valves, the locking recess formedbetween two spaced-apart teeth or protrusions that extend axially awayfrom (and are generally perpendicular to) the valve surface; and (ii) ablade tooth that extends axially away from an end surface of the plungerand is configured to be received with the locking recess to engage thevalve. The locking recess formed by the teeth and blade tooth may beconfigured to be of complimentary shapes and sizes so that the bladetooth abuts against the surface of the teeth when the blade tooth isreceived with the locking recess. In various embodiments, a surface ofthe teeth may be concave in nature and a surface of the blade tooth maybe convex in nature. In alternative embodiments, the positioning featuremay further include an end cap on the blade tooth, the end cap includeangled surfaces that correspond with tapered surfaces that furtherdefine the locking recess of the valve.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood with reference to the followingdetailed description of the invention and the drawings in which:

FIG. 1 schematically illustrates an eye treatment system in which acassette couples an eye treatment probe with an eye treatment console;

FIGS. 2A and 2B are exploded views of an exemplary surgical cassettemanifold for use in the system of FIG. 1;

FIG. 3A is perspective front view of a front housing of an exemplarysurgical cassette manifold;

FIG. 3B is perspective back view of a front housing of an exemplarysurgical cassette manifold;

FIG. 4A is a front perspective view of a rear housing of an exemplarysurgical cassette manifold;

FIG. 4B is a back perspective view of a rear housing of an exemplarysurgical cassette manifold;

FIG. 5 is a side view of the front side of the rear housing illustratedin FIG. 4A;

FIG. 6 is a back perspective view of the rear housing illustrated inFIG. 4B;

FIG. 7A is a cross-sectional view taken along the line 7A-7A in FIG. 6;

FIG. 7B is a cross-sectional view taken along the line 7B-7B in FIG. 6;

FIG. 7C is a cross-sectional view taken along the line 7C-7C in FIG. 6;

FIG. 8 is a cross-sectional view of one or more valve assemblies of thesurgical cassette manifold of FIG. 4B;

FIG. 9A is a side perspective view of a valve assembly of the surgicalcassette manifold of FIG. 4B;

FIG. 9B is a top perspective view of a valve assembly of the surgicalcassette manifold of FIG. 4B;

FIG. 10A is a partial side perspective view of an eye treatment consoleof FIG. 1, illustrating a valve actuation mechanism in the console;

FIG. 10B1 and 10B2 are perspective views of a solenoid valve actuationmember of the valve actuation mechanism of FIG. 10A, in particular, forexample, for an aspiration valve and an irrigation vent valve,respectively;

FIG. 10C is a partial back perspective view of the valve assembly ofFIG. 4B;

FIG. 10D is a top perspective view of an alternative valve assembly ofthe surgical cassette manifold of FIG. 4B; and

FIG. 11 is a perspective view of a surgical cassette manifold with tubesand a drainage page attached to transport fluid into or receive fluidfrom the cassette manifold.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whilethe invention will be described in conjunction with the embodiments, itwill be understood that they are not intended to limit the invention tothose embodiments. On the contrary, the invention is intended to coveralternatives, modifications, and equivalents, which may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

Referring to FIG. 1, a system 10 for treating an eye E of a patient Pgenerally includes an eye treatment probe handpiece 12 coupled to aconsole 14 by a cassette 100 mounted on the console. Handpiece 12 mayinclude a handle for manually manipulating and supporting an insertableprobe tip. The probe tip has a distal end which is insertable into theeye, with one or more lumens in the probe tip allowing irrigation fluidto flow from the console 14 and/or cassette 100 into the eye. Aspirationfluid may also be withdrawn through a lumen of the probe tip, with theconsole 14 and cassette 100 generally including a vacuum aspirationsource, a positive displacement aspiration pump, or both to helpwithdraw and control a flow of surgical fluids into and out of eye E. Asthe surgical fluids may include biological materials that should not betransferred between patients, cassette 100 will often comprise adisposable (or alternatively, re-sterilizable) structure, with thesurgical fluids being transmitted through conduits of the cassette thatavoid direct contact in between those fluids and the components ofconsole 14.

When a distal end of the probe tip of handpiece 12 is inserted into aneye E, for example, for removal of a lens of a patient with cataracts,an electrical conductor and/or pneumatic line (not shown) may supplyenergy from console 14 to an ultrasound transmitter of the handpiece, acutter mechanism, or the like. Alternatively, the handpiece 12 may beconfigured as an irrigation/aspiration (I/A) or vitrectomy handpiece.Also, the ultrasonic transmitter may be replaced by other means foremulsifying a lens, such as a high energy laser beam. The ultrasoundenergy from handpiece 12 helps to fragment the tissue of the lens, whichcan then be drawn into a port of the tip by aspiration flow. So as tobalance the volume of material removed by the aspiration flow, anirrigation flow through handpiece 12 (or a separate probe structure) mayalso be provided, with both the aspiration and irrigations flows beingcontrolled by console 14.

So as to avoid cross-contamination between patients and/or to avoidincurring excessive expenditures for each procedure, cassette 100 andits conduit 18 may be disposable. Alternatively, the conduit or tubingmay be disposable, with the cassette body and/or other structures of thecassette being sterilizable. Regardless, the disposable components ofthe cassette are typically configured for use with a single patient, andmay not be suitable for sterilization. The cassette will interface withreusable (and often quite expensive) components of console 14, which mayinclude one or more peristaltic pump rollers, a Venturi or other vacuumsource, a controller 40, and the like.

Controller 40 may include an embedded microcontroller and/or many of thecomponents common to a personal computer, such as a processor, data bus,a memory, input and/or output devices (including a touch screen userinterface 42), and the like. Controller 40 will often include bothhardware and software, with the software typically comprising machinereadable code or programming instructions for implementing one, some, orall of the methods described herein. The code may be embodied by atangible media such as a memory, a magnetic recording media, an opticalrecording media, or the like. Controller 40 may have (or be coupled to)a recording media reader, or the code may be transmitted to controller40 by a network connection such as an internet, an intranet, anEthernet, a wireless network, or the like. Along with programming code,controller 40 may include stored data for implementing the methodsdescribed herein, and may generate and/or store data that recordsparameters corresponding to the treatment of one or more patients. Manycomponents of console 14 may be found in or modified from knowncommercial phacoemulsification systems from Abbott Medical Optics Inc.of Santa Ana, Calif.; Alcon Manufacturing, Ltd. of Ft. Worth, Tex.;Bausch and Lomb of Rochester, N.Y.; and other suppliers.

In illustrative embodiments, a surgical cassette manifold 101 isconfigured to be coupled and removed from the console 14 after useduring a surgical procedure. FIGS. 2A and 2B illustrate a surgicalcassette manifold 101 of the present invention, including components ofthe surgical cassette manifold 101. Cassette or surgical cassette 100 isan assembled surgical cassette manifold 101 having fluid pathways andconnected tubing configured to manage one or more of the following:fluid inflow, fluid outflow, fluid vacuum level, and fluid pressure in apatient's eye E when the cassette 100 is coupled with console 14.

As shown in FIGS. 2A and 2B, the surgical cassette manifold 101 has afront housing 102, a rear housing 104, a first tubing 106, and a secondtubing 108. Rear housing 104 may also have a gasket 110 co-molded orover-molded with rear housing 104. As illustrated in FIGS. 2A and 2B,the rear housing 104, the front housing 102, or a combination of bothmay have axial mating plane surfaces 105. Axial mating plane surfaces105 are outer border faces of the back housing 104 and/or front housing102 that form a surface mating with console 14 within a cassettereceiver 210 of the console 14 after loading.

FIG. 3A and 3B illustrate the front housing 102 in more detail. FIG. 3Ashows a perspective view of an illustrative embodiment of a frontsurface 144 of front housing 102, the front surface 144 including ahandle 112 (e.g. finger grip handle), a drain port 114, and anattachment clip 116. A drain bag 16, as seen in FIG. 11, may be attachedto the front surface 144 of front housing 102 via the drain port 114 andattachment clip 116 such that, when the surgical cassette 100 is coupledwith the console 14 and fluid is aspirated from an eye E of a patient P,the fluid is capable of being collected in the drainage bag 16 via thedrain port 114. The drain bag 16 may be supported on surgical cassettemanifold 101 by the attachment clip 116 and/or drain port 114. FIG. 3Bshows a perspective view of a back surface 146 of the front housing 102,the back surface 146 having in illustrative embodiments one or moremolded fluid channels 118, a reservoir 120, a first pump ramp or profile122 configured and dimensioned for mating with a peristaltic pump, andan optional second pump ramp or profile 124 configured and dimensionedfor mating with a peristaltic pump.

FIGS. 4A and 4B illustrate the rear housing 104 in more detail. FIG. 4Ais a front perspective view of the rear housing 104 and FIG. 4B is aback perspective view of rear housing 104. In illustrative embodiments,rear housing 104 includes a front surface 142 and a back surface 148.The rear housing 104 may include a reservoir 119, upper tube connections134, optional lower tube connections 136, and one or more tubingretainer clips 138. In an embodiment, upper tube connections 134 arelocated between the front surface 142 and back surface 148 and have aslight taper from bottom toward the top so that the tubing stays on theupper tube connections 134, as illustrated in FIG. 4A. Lower tubeconnection 136 may similarly be located between front surface 142 andback surface 148 and have a tapered head to secure second tubing 108 tolower tube connections 136. As shown in FIG. 4A, rear housing 104 mayinclude the gasket 110 co-molded or over-molded to it. Rear housing 104is configured to be coupled together (for example, in a snap fitengagement) with front housing 102 to contain gasket 110 there between.

In illustrative embodiments, the surgical cassette 100 may include atleast one peristaltic pump tube 106. FIGS. 2A and 2B show the backsideof surgical cassette 100 and a peristaltic pump tube 106. In anembodiment, pump tube 106 may have a first end and a second end thatcouple with upper tube connections 134. The peristaltic pump tube 106may be an elastomeric length of tubing that is configured to generatepositive displacement of fluid flow in the direction of a pump roller(not shown) of the console 14 when a portion of the peristaltic pumptube 106 is compressed between the peristaltic pump rollers of console14 and the ramp 122 of the front housing 102 of surgical cassette 100.It is also envisioned that any type of flow-based pump and correspondingcomponents may be used with surgical cassette 100. In an embodiment, theramp 122 may include a backing plate pump profile 109 comprised ofcontoured surfaces formed on the inside of the front housing 102 ofcassette 100 to provide moving compression on the tubing 106 whilecreating peristaltic pumping flow through the cassette 100, particularlythrough pump tube 106. In various embodiments, pump tube 106 may beformed to partially conform to the shape of ramp 122, as illustrated,for example, in FIG. 7A.

In illustrative embodiments, the surgical cassette 100 may optionallyinclude a second peristaltic pump tube 108, as illustrated in FIGS. 2Aand 2B. The second pump tube 108 may be configured of similar size andshape as first pump tube 106. In an embodiment, second pump tube 108 mayhave a first end and a second end that couple with lower tubeconnections 136. Once surgical cassette manifold 101 is assembled,second tubing 108 and ramp 124 are configured to couple with aperistaltic rollers (not shown) located on console 14 to create aperistaltic pump. In an embodiment, lower tube connections 136 are onthe same axis, i.e. there is axial alignment of the inflow and outflowof the second tubing 108, and maintain a specific distance apartresulting in a more accurate peristaltic pump due to a controlled lengthof the second tubing 108, which provides a consistent flow rate and aconsistent interface with ramp 124 and peristaltic rollers. Moreover,such aligned and consistent interfaces results in less noise/soundgenerated by the peristaltic pump during operation. Such axial alignmentmay also be provided between upper tube connections 134 and first pumptube 106.

During assembly, rear housing 104 is mated with front housing 102, firsttube 106 is configured to conform with first pump ramp 122, and secondtube 108 is configured to conform with second pump ramp 124. First pumpramp 122 is configured and dimensioned for mating with a firstperistaltic pump (not shown) located within the console 14. Second tube108 is configured to conform with second pump ramp 124. Second pump ramp124 is configured and dimensioned for mating with a second peristalticpump (not shown) located within the console 14. Reservoir 120 of fronthousing 102 and reservoir 119 of rear housing 102 are configured to begenerally aligned to create a void 117 within cassette manifold 101defined by reservoir 120 and reservoir 119, as illustrated for examplein FIG. 7C. Void 117 is configured to retain fluid pumped into cassette100 from the handpiece 12 by the first peristaltic pump. The fluidretained in void 117 by reservoirs 119 and 120 may then be pumped out ofcassette 100 to drain port 114 by the second peristaltic pump.

In illustrative embodiments, reservoir 120 may have a sump 121. Sump 121is a portion of reservoir 120 that extends below a bottom 120 c ofreservoir 120 that promotes fluid to flow from the reservoir 120 to sump121 and to the lower tube connection 136. Sump 121 may (1) reduceturbulence of the tank; and (2) ensure a drain inlet port 133 a of thelower tube connection 136 is always below the level of fluid inside thevoid 117, therefore fluid is consistently pumped out of the cassette 100and not air (which may cause the drain bag 16 to balloon).

In illustrative embodiments, tubing retainer clips 138 (shown in FIGS.2A and 2B) may be provided to protrude substantially perpendicularlyfrom a plane of the back side 122 of front housing 102 to secure thefirst pump tube 106. Tubing retainer clips 138 are configured anddimensioned to assist with easy assembly of surgical cassette manifold101 and maintaining first tubing 106 in a specific orientation afterassembly. Similar tubing retainer clips 138 may be positioned to retainsecond pump tube 108.

In illustrative embodiments, gasket 110 may be over-molded with backhousing 104 such that gasket 110 is secured to back housing 104, andgasket 110 is further configured to be sandwiched between front housing102 and back housing 104 when the cassette 100 is assembled together. Asshown in FIG. 3B, front housing 102 also may have one or more sealchannels 125. Seal channels 125 may be configured and dimensioned tomate with gasket 110. Specifically, seal channels 125 may be configuredand dimensioned to mate with a seal lip 126 that extends outwardly orperpendicularly from a front surface 140 of gasket 110. Seal lip 126 isa part of gasket 110 configured to create a seal or lid over moldedfluid channels 118 of front housing 102. The seal lip 126 may have anydimension suitable for mating with seal channel 125. In an embodiment,seal lip 126 may be tapered, starting thicker at its proximal end andbecoming thinner towards its distal end. In another embodiment, seal lip126 may be slightly larger than seal channel 125 to create a snug fit.Seal lip 126 provides positioning alignment on front housing 102 andrear housing 104.

Gasket 110 may be formed separately from rear housing 104 and thenco-molded or over-molded onto rear housing 104. Gasket 110 includes afront surface 140 and a back surface 141 such that the front surface 140is adjacent the front housing 102 and the back surface 141 is adjacentthe rear housing 104 when the front housing 102 is coupled to the rearhousing 104. The front surface 140 of gasket 110 includes the seal lip126 which extends away or protrudes in a substantially perpendiculardirection from a plane of gasket 110 and rear housing 104, asillustrated in FIGS. 4A and 5. Gasket 110 may include a pressure/vacuumsensor diaphragm 128, an aspiration vent valve 130, and/or an irrigationvalve 132, discussed in more detail below.

In an embodiment, gasket 110 may be molded, co-mold, or two-shot moldedonto or with rear housing 104. Molding gasket 110 onto rear housing 104in such a manner reduces or eliminates a leak path which is possiblewith molded fluid channels when using two different materials. In anembodiment, a method of eliminating leaking of molded fluid channels bycombining two different materials for creating a proper seal isenvisioned resulting in an easier manufacturing method by creating aself-aligning gasket 110. In an alternative embodiment, when assemblingrear housing 104 to front housing 102, mating of seal lip 126 and sealchannel 125 can be achieved using a plurality of alignment pins 127 onrear housing 104 that mate with counterpart pin holes 129 on fronthousing 102, as illustrated in FIGS. 3B and 4A. Using alignment pins 127and pin holes 129 as opposed to relying only on the flexible seal lip126 and seal channel 125 allows for an easier and more efficientassembly process. Molding gasket 110 onto or with rear housing 104results in pre-alignment/pre-keyed/pre-orientation of seal lip 126 forproperly sealing with molded fluid channels 118 on front housing 102,thus reducing or even eliminating leaking and increasing ease ofmanufacture.

In illustrative embodiments, when gasket 110 is properly placed betweenfront housing 102 and rear housing 104, and front and rear housings 102and 104 are coupled together, molded fluid channels 118 of front housing102 and portions of the gasket 110 between the seal lips 126 form atleast one sealed flow channel or pathway 150 through the cassette 100.Referring to FIGS. 4A and 4B, sealed flow channel 150 includes one ormore fluid flow pathways formed by raised surfaces (e.g. seal channels125 of front housing 102) allowing fluid to flow in internal channelsbetween the raised surfaces and outer perimeter sealing (e.g. seal lips126) border of gasket 110 to retain fluid within the manifold fluid flowchannels 118 under positive pressure and vacuum conditions. Accordingly,the sealed flow channel 150 directs the flow of fluids through thecassette manifold 101 as the peristaltic pumps operate. Sealed flowchannel 150 is generally in fluid communication with fluid reservoir120. The sealed flow channel 150, comprising of the molded fluidchannels 118 and gasket 110, accordingly eliminates the need for tubingto transport fluid through the cassette 100.

In various embodiments, sealed flow channel 150 may include anirrigation flow channel 150 a and an aspiration flow channel 150 b.Irrigation flow channel 150 a is configured as a pathway with an inlettubing port (not shown) from a balance salt solution (BSS) irrigationbottle (not shown) metered by one or more irrigation valves to one ormore of the following: (1) an irrigation tubing outlet port (not shown)connected to an external surgical handpiece 12 flowing fluid to the eye,which may be metered or controlled by irrigation valve 132; or (2) aventing line (not shown) providing BSS irrigation fluid into theaspiration flow channel 150 b. In various embodiments, irrigation flowchannel 150 a may be positioned within cassette 100 to transport fluidthat is driven into the cassette 100 from a gravity-driven irrigationbottle, through the cassette 100, and to the external handpiece 12 toprovide irrigation fluid to the surgical field. In illustrativeembodiments, fluid may be transported into the cassette 100 via anirrigation tube 111, as illustrated in FIG. 11. Other means of flow forirrigation fluid through a cassette and to a handpiece 12 are known inthe art.

Aspiration flow channel 150 b is configured as a pathway for fluid toflow from the external handpiece 12 to the drainage port 114 after thefluid or other particles have been aspirated from a patient's eye E. Inillustrative embodiments, during aspiration of a patient's eye E, fluidflows through the aspiration flow channel 150 b in various manners. Forinstance, fluid may flow into the first pump tube 106 via a pump tubeinlet 137 a. Upper tube connections 134 of rear housing 104 may comprisepump tube inlet 137 a and pump tube outlet 137 b to transport fluid frompump tube inlet 137 a, through the first pump tube 106, and then throughthe pump tube outlet 137 b as the first peristatic pump operates. Inillustrative embodiments, aspiration flow channel 150 b extends frompump tube outlet 137 b to transport fluid through the cassette manifold101. Aspiration flow channel 150 extends from pump tube outlet 137 b toreservoir 120 along a first pathway 160, as illustrated in FIGS. 4A and5. Fluid is therefore transported into reservoir 120 via first pathway160. Fluid may be transported out of reservoir 120 via a drain pumpinlet port 133 a. Lower tube connections 136 may comprise drain pumpinlet port 133 a and a drain pump outlet 133 b to transport fluid fromdrain pump inlet port 133 a, through the second pump tube 108, and thenthrough the drain pump outlet port 133 b as the second peristatic pumpoperates. Drain pump outlet 133 b is coupled with a drain bag 16 toallow fluid to be removed from reservoir 120 via the second peristalticpump, as illustrated in FIGS. 4A and 5. Illustratively, a second pathway162 of flow channel 150 runs in a vertical direction from a lower tubeconnection 136 (that is fluidly connected to the second tubing 108associated with a second peristaltic pump) to drain port 114 out to thedrain bag 16. Other configurations of an aspiration flow channel 150 bare envisioned within the scope of this disclosure.

The aspiration flow channel 150 b may further include a venting port forventing fluid inflow from a BSS irrigation bottle or the irrigation flowchannel 150 a, which may be metered into the aspiration flow channel 150b by the aspiration vent valve 130. Aspiration vent valve 130 isconfigured to permit introduction of irrigation fluid into theaspiration flow channel 150 b, which may be metered by vent valve 130,to, for example, reduce vacuum level in the aspiration flow channel 150b. Such reduction of vacuum level may be necessary following obstructionor occlusion of the tip of handpiece 12 by, for example, particles beingaspirated from the eye E.

In illustrative embodiments, to monitor and control the flow of fluidthrough the sealed flow channel 150, the cassette 100 may include apressure/vacuum sensor diaphragm 128, a aspiration vent valve 130,and/or an irrigation valve 132, as illustrated in FIG. 6. Specifically,the pressure/vacuum sensor diaphragm 128, aspiration vent valve 130,and/or irrigation valve 132 may be formed within the gasket 110. Thegasket 110 adjacent the aspiration flow channel 150 b may include thevacuum/pressure sensor diaphragm 128 and aspiration vent valve 130, andthe gasket 110 adjacent the irrigation flow channel 150 a may includethe irrigation valve 132.

In illustrative embodiments, vacuum/pressure sensor diaphragm 128 may bea sealed flexible annular membrane with a central magnetic coupling disk212. The vacuum/pressure sensor diaphragm 128 may be positioned to be influid connection with the aspiration flow channel 150 b. The centralmagnetic coupling disk 212 deforms: (1) proportionally outwards underfluid pressure conditions in the aspiration flow channel 150 b,compressing a magnetically-coupled force displacement transducer 208 ofconsole 14 (as illustrated in FIG. 10A); and (2) proportionally inwardsunder fluid vacuum conditions in the aspiration flow channel 150 b,extending a magnetically-coupled force displacement transducer 208 ofconsole 14. Such deformation of the vacuum/pressure sensor diaphragm 128allows for non-fluid contact measurement of fluid vacuum levels of theaspiration flow channel 150 b of surgical cassette manifold 101.

Referring to FIGS. 4A and 4B, irrigation valve 132 of surgical cassette100, which in an embodiment may have a dome-like shape, may be anelastomeric deformable surface which allows irrigation flow from a BSSbottle to external surgical handpiece 12 when uncompressed and shuts offflow in the irrigation flow channel 150 a when the irrigation valve 132deforms into the irrigation flow channel 150 a (towards the fronthousing 102). Similarly, aspiration vent valve 130, which in anembodiment may have a dome-like shape, may be an elastomeric deformablesurface which allows irrigation flow (from the BSS bottle or irrigationflow channel 150 a) into the aspiration flow channel 150 b that iscoupled with the external surgical handpiece 12. When irrigation fluidis introduced into the aspiration flow channel 150 b, the vacuum levelof the aspiration flow channel 150 b, and accordingly the vacuum levelof aspiration occuring in the patient's eye E, is reduced. In variousembodiments, the reduction could be such that aspiration flow is shutoff when the aspiration vent valve 130 is deformed into fluid channels118 (towards the front housing 102). Accordingly, the level of fluidflow in the sealed fluid flow channel 150 may be controlled based uponthe level of compression of valves 130 and 132—from full flow tointermediate flow to no flow.

In an illustrative embodiment, as illustrated in FIGS. 3A and 3B,surgical cassette 100 may have one or more valve control surfaces 115.Valve control surfaces 115 may be a raised sealing surface in manifoldfluid flow channels 118 of front housing 102 that provide a point ofcontact for valve 130 or 132 when they are deformed or activated towardthe fluid flow channels 118 of front housing 102.

The interaction between the console 14 and cassette 100 will now bedescribed. In illustrative embodiments, a fluidics module 200 accordingto an embodiment of the present invention comprises an assembly ofcomponents mounted to the console 14 for interfacing with the surgicalcassette 100, as illustrated in FIG. 10A. A fluidics module 200 may haveone or more of the following components: (i) a cassette receiver 210,(ii) a cassette pre-load detection pin, and/or (iii) a pre-loaddetection switch. For instance, a cassette receiver 210 may be a sectionof fluidics module 200 defining an engagement area for loading andaligning surgical cassette 100 in its intended position relative tovarious components of fluidics module 200. In other embodiments,fluidics module 200 may have one or more pump roller assemblies (notshown) configured with multiple roller elements in a circular orsubstantially circular pattern which produce peristaltic flow-basedfluid transport when rotated against compressed fluid-filled peristalticpump tubes 106 and 108. Other components of a fluidics module aregenerally known in the art and may be incorporated into the fluidicsmodule 200 of the present disclosure to assist with interfacing thesurgical cassette 100 with the console 14.

In illustrative embodiments, fluidics module 200 may have a forcedisplacement transducer 208. Force displacement transducer 208 may beelectrically or otherwise connected with the controller 40. Forcedisplacement transducer 208 may operate by means of a magnetic coupling(via, for example, a magnet 214) with the central magnetic coupling disk212 of the vacuum/pressure sensor diaphragm 128. Specifically, a vacuumoccurrence of fluid inside the aspiration flow channel 150 b formed bymanifold fluid flow channels 118 will cause deformation inwards of thevacuum/pressure sensor diaphragm 128 (and the magnetic coupling disk212) in the surgical cassette 100, and the magnetic force from thecoupling disk 212 upon the magnet 214 of the force displacementtransducer 208 will axially extend force displacement transducer 208outward away from the fluidics module 200, resulting in a change of anelectrical output signal to the controller 40 in proportion to a vacuumlevel. Conversely, positive fluid pressure in the aspiration flowchannel 150 a formed by manifold fluid flow channels 118 results in anoutward extension of vacuum/pressure sensor diaphragm 128 andcompression of the force displacement transducer 208 inward toward thefluidics module 200.

In an embodiment, fluidics module 200 may have an irrigation valveplunger 230 and an aspiration vent valve plunger 232. Irrigation valveplunger 230 axially extends away from the fluidics module 200 and iscontrolled (e.g. by a solenoid (not shown) in the console 14) to move ina direction towards or away from the fluidics module 200 when controlledby the controller 40. The irrigation valve plunger 230 is configured tocompress the irrigation valve 132 of surgical cassette 100, resulting ina decrease or shutoff of irrigation flow in the irrigation flow channel150 a to external irrigation tubing line to the handpiece 12. Irrigationvalve plunger 230 may also operate by a spring-loaded retraction of theplunger to allow varying levels of irrigation flow. Similarly, ventvalve plunger 232 may be controlled by controller 40 and have an axialextension of the plunger 232 that compresses aspiration vent valve 130of surgical cassette 100, resulting in a decrease or shutoff ofirrigation venting flow to the aspiration flow channel 150 b. Aspirationvent valve plunger 232 may also operate by a spring-loaded retraction ofthe plunger to allow irrigation pressure fluid flow to vent inaspiration flow channel 150 b if the pressure/vacuum level requiresreduction.

The irrigation valve plunger 230 and aspiration vent plunger 232 areconfigured with an end surface 234 and 236, respectively, that areconfigured to deform the irrigation valve 132 and aspiration vent valve130, respectively, to block flow of fluid through the flow channel 150positioned next to the irrigation valve 132 and aspiration vent valve130. Specifically, for example, when the irrigation valve plunger 230and the aspiration vent plunger 232 are engaged into the flow channel150, the end surfaces 234 and 236 may be configured to contact or sealwith the back surface 146 of the front housing 102, reducing orcompletely stopping the flow of fluid through the flow channel 150. Inillustrative embodiments, the end surface 234 and 236 may abut againstthe valve control surfaces 115 (having the irrigation valve 132 andaspiration vent valve 130 sealing with the valve control surfaces 115)to reduce or eliminate flow of fluid.

In illustrative embodiments, the end surfaces 234 and 236 and the valves132 and 130 are generally configured to be similar in size and shape, inorder for the end surfaces 234 and 236 to deform the valves 132 and 130.As the end surfaces 234 and 236 engage with the valves 132 and 130, itis desirable to avoid any potential for asymmetrical loading orotherwise deforming the valves in such a way that would compromise thesealing. Further, by ensuring an evenly distributed load distribution,the overall force required upon the plunger (e.g. by the solenoid) maybe reduced to a minimal level required to engage the valves.

In illustrative embodiments, the irrigation valve plunger 230 andirrigation valve 132 are configured with a positioning feature 250 toavoid asymmetrical loading upon the valve 132,—as illustrated in FIGS.6, 9A, 9B, 10A, 10B2 and 10C, for example. Positioning feature 250includes a locking recess 252 on a back surface 240 of irrigation valve132, the locking recess 252 being positioned along the back surface 141of gasket 110. Locking recess 252 is formed between two spaced-apartteeth 242 of positioning feature 250 that extend axially away from (andare generally perpendicular to) the back surface 240, as illustrated forexample in FIGS. 6, 7B, 9A, 9B, and 10C. Positioning feature 250 furtherincludes a blade tooth 246 that extends axially away from the endsurface 234 of the irrigation valve plunger 230. In illustrativeembodiments, blade tooth 246 is configured to be received with thelocking recess 252 formed by the spaced-apart teeth 242 and to engagewith the irrigation valve 132. As the irrigation valve plunger 230engages with the irrigation valve 132, blade tooth 246 may abut againstthe back surface 240 of the irrigation valve 132 between thespaced-apart teeth 242. Accordingly, positioning feature 250 ensuresirrigation valve plunger 230 is properly aligned with irrigation valve132 as irrigation valve plunger 230 is moved toward irrigation valve132, for uniform contact therewith, and further permits irrigation valve132 to be deformed uniformly by irrigation valve plunger 230 whenirrigation valve plunger 230 applies force to irrigation valve 132.Locking recess 252 and blade tooth 246 may be generally each alignedalong a first axis A1.

In illustrative embodiments, and as illustrated in FIG. 10B2, bladetooth 246 may include a first contact surface 248 and a second contactsurface 249. Similarly, as illustrated in FIGS. 7B and 9A, spaced-apartteeth 242 may include first and second receiving surfaces 254 and 255.As blade tooth 246 is received within locking recess 252, first contactsurface 248 may engage with or abut against first receiving surface 254,and second contact surface 249 may engage with or abut against secondreceiving surface 255.

First contact surface 248, second contact surface 249, first receivingsurface 254, and second receiving surface 255 may be configured in avariety of shapes or sizes. For instance, first contact surface 248 mayexist is a single plane Pl, and second contact surface 249 may exist ina single plane P2, where plane P1 is parallel to plane P2, asillustrated in FIG. 10B2. First and second receiving surface 254 and 255may mirror first and second contact surfaces 248 and 249 and each existin a single plane. Alternatively, first contact surface 248 may beconvex or concave in nature, and second contact surface 249 may beoppositely convex or concave in nature. First and second receivingsurfaces 254 and 255 may again mirror the first and second contactsurfaces 248 and 249 to abut against the convex or concave first andsecond contact surfaces 248 and 249, as illustrated in FIGS. 9A and 9B.Other shapes or forms of first contact surface 248, second contactsurface 249, first receiving surface 254, and second receiving surface255 are envisioned herein. First and second receiving surfaces 254 and255 may be spaced apart distance D2, as illustrated in FIGS. 7B and 8,to receive blade tooth 246.

In illustrative embodiments, first receiving surface 254 may include afirst angled portion 270 and a second angled portion 272, where thefirst angled portion 270 extends from a bottom circumference surface ofthe teeth 242 to generally a center axis C of the teeth 242, and thesecond angled portion 272 extends from a top circumference surface ofthe teeth 242 to generally the center axis C, as illustrated in FIGS. 9Aand 9B. As illustrated in FIG. 9B, first angled portion 270 may extendat a first angle 280 from axis A1, and second angled portion 272 mayextend at a second angle 282 from axis A1, whereby the second angle 282is different than the first angle 280. Accordingly, the teeth 242 may beshaped differently along the first angled portion 270 and second angledportion 272. In another embodiment, the first angle 280 and the secondangle 282 may be similar or the same.

In illustrative embodiments, blade tooth 246 may further include an endcap 256 that is configured to further guide blade toot into lockingrecess 252. In an exemplary embodiment, as illustrated in FIG. 10B2, endcap 256 may include tapered sides 258. Tapered sides 258 may engage withand abut against corresponding tapered surfaces 262 that extend betweenthe back surface 240 of the irrigation valve and first and secondreceiving surfaces 254 and 255.

In illustrative embodiments, the aspiration vent valve plunger 232 andaspiration vent valve 130 are configured with a positioning feature 220respectively, to avoid asymmetrical loading upon the valve 130, asillustrated for example in FIGS. 10A, 10B1, 10C and 10D. The positioningfeature 220 may be substantially similar to the positioning feature 250described above. For instance, positioning feature 220 includes alocking recess 222 on a back surface 218 of aspiration vent valve 130,the locking recess 222 being positioned along the back surface 141 ofgasket 110. Locking recess 222 is formed between two spaced-apart teeth224 of positioning feature 220 that extend axially away from (and aregenerally perpendicular to) the back surface 218, as illustrated forexample in FIGS. 6, 7B, 8, 9A, and 10C. Positioning feature 220 furtherincludes a blade tooth 226 that extends axially away from the endsurface 236 of the aspiration vent valve plunger 232. In illustrativeembodiments, blade tooth 226 is configured to be received with thelocking recess 222 formed by the spaced-apart teeth 224 and to engagewith the aspiration vent valve 130. As the aspiration vent valve plunger232 engages with the aspiration vent valve 130, blade tooth 226 may abutagainst the back surface 218 of the aspiration vent valve 130 betweenthe spaced-apart teeth 224. Accordingly, positioning feature 220 ensuresaspiration vent valve plunger 232 is properly aligned with aspirationvent valve 130 as aspiration vent valve plunger 232 is moved towardaspiration vent valve 130, for uniform contact therewith, and furtherpermits aspiration vent valve 130 to be deformed uniformly by aspirationvent valve plunger 232 when aspiration vent valve plunger 232 appliesforce to aspiration vent valve 130. Locking recess 222 and blade tooth226 may be generally each aligned along a second axis A2.

In illustrative embodiments, blade tooth 226 may include a first contactsurface 228 and a second contact surface 229. Similarly, spaced-apartteeth 224 may include first and second receiving surfaces 238 and 239.As blade tooth 226 is received within locking recess 222, first contactsurface 228 may engage with or abut against first receiving surface 238,and second contact surface 229 may engage with or abut against secondreceiving surface 239.

First contact surface 228, second contact surface 229, first receivingsurface 238, and second receiving surface 239 may be configured in avariety of shapes or sizes. For instance, first contact surface 228 mayexist is a single plane Pl, and second contact surface 229 may exist ina single plane P2, where plane P1 is parallel to plane P2. First andsecond receiving surface 238 and 239 may mirror first and second contactsurfaces 228 and 229 and each exist in a single plane. Alternatively,first contact surface 228 may be convex or concave in nature, and secondcontact surface 229 may be oppositely convex or concave in nature. Firstand second receiving surfaces 238 and 239 may again mirror the first andsecond contact surfaces 228 and 229 to abut against the convex orconcave first and second contact surfaces 228 and 229. Other shapes orforms of first contact surface 228, second contact surface 229, firstreceiving surface 238, and second receiving surface 239 are envisionedherein. First and second receiving surfaces 238 and 239 may be spacedapart distance Dl, as illustrated in FIGS. 7B and 8, to receive bladetooth 246. Distance Dl may be smaller than, the same as, or larger thandistance D2, depending on the design of the valves 130 and 132 and thecassette 100.

In illustrative embodiments, first receiving surface 238 may include afirst angled portion 284 and a second angled portion 286, where thefirst angled portion 284 extends from a bottom circumference surface ofthe teeth 224 to generally a center axis C of the teeth 224, and thesecond angled portion 286 extends from a top circumference surface ofthe teeth 224 to generally the center axis C. As illustrated in FIG.10D, first angled portion 284 may extend at a first angle 290 from axisA2, and second angled portion 286 may extend at a second angle 292 fromaxis A2, whereby the second angle 292 is different than the first angle290. Accordingly, the teeth 224 may be shaped differently along thefirst angled portion 284 and second angled portion 286.

In illustrative embodiments, blade tooth 226 may further include an endcap 274 that is configured to further guide blade tooth into lockingrecess 222. In an exemplary embodiment, as illustrated in FIG. 10B1, endcap 274 may include tapered sides 276. Tapered sides 276 may engage withand abut against corresponding tapered surfaces 264 that extend betweenthe back surface 218 of the vent valve 130 and first and secondreceiving surfaces 238 and 239.

In illustrative embodiments, blade tooth 226 may be fixedly coupled to arectangular base 260 that is retained within the console 14, asillustrated in FIG. 10B1. The base 260 may be configured to be receivedwithin a similarly-shaped aperture (not shown) of console 14 to preventor reduce unintended rotation of blade tooth 226, thereby preventing orreducing misalignment with the locking recess 222.

In an embodiment, surgical cassette manifold 101 may be madesubstantially of a plastic material except for gasket 110. The plasticmaterial may be acrylonitrile-butadiene-styrene (ABS), polycarbonate(PC), polyethylene, viton, or other rigid plastic or plastic material.In addition, the material may be such that it is transparent enabling auser to visualize various features of surgical cassette manifold 101.For example, all components may be transparent, including reservoir 120.In an embodiment, one or more lights emitted from console 14 may beshone through surgical cassette manifold 101 to provide a backlight andallow a user to visualize the fluid flow as it flows from handpiece 12through sealed fluid flow channel 150 into reservoir 120 and out to thedrain bag 16. In an embodiment, the backlight may also be used as asurgical cassette manifold type detector.

All references cited herein are hereby incorporated by reference intheir entirety including any references cited therein.

Although the present invention has been described in terms of specificembodiments, changes and modifications can be carried out withoutdeparting from the scope of the invention which is intended to belimited only by the scope of the claims.

1-10. (canceled)
 11. A surgical system, comprising: a console, theconsole including one or more moveable plungers; a cassette, thecassette including a front plate and a gasket formed with one or moredeformable valves, the one or more valves configured to generally alignwith the one or more plungers when the cassette is connected to theconsole; and a positioning feature, the positioning feature includingspaced-apart teeth coupled to a back surface of the one or more valvesand extending axially away from the back surface, the spaced-apart teethforming a locking recess, the positioning feature further including ablade tooth coupled to one or more plungers, the blade tooth dimensionedsimilar to the dimension of the locking recess to be received within thelocking recess.
 12. The surgical system of claim 11, wherein the bladetooth is coupled to an end surface of the one or more plungers.
 13. Thesurgical system of claim 12, wherein the blade tooth includes a taperedsurface that abuts against a tapered surface of the spaced-apart teethwhen the blade tooth is received within the locking recess.
 14. Thesurgical system of claim 12, wherein the blade tooth abuts against theback surface of the one or more valves and applies pressure to the oneor more valves to deform the valve toward the front plate.
 15. Thesurgical system of claim 11, wherein the front plate and gasket form aflow channel for fluid to flow through the cassette, and where the oneor more deformable valves are configured to restrict or block flow offluid through the flow channel.
 16. The surgical system of claim 15,wherein the positioning feature permits substantially uniform forceapplication from the one or more plungers to the one or more valves whenthe plungers are moved toward the gasket.
 17. The surgical system ofclaim 11, wherein the moveable plunger is controlled via a controllerwithin the console.
 18. The surgical system of claim 17, wherein themoveable plunger is operated by a solenoid.
 19. The surgical system ofclaim 17, wherein the movable plunger includes an asymmetrical base thatis retained by the console.
 20. A gasket, comprising: a body, whereinthe body is deformable and has a front surface and a back surface; andone or more valves integrated with the body and having a front surfaceand a back surface, the back surface of the one or more valves includingone or more positioning lips that extend in a direction generallyperpendicular to the body and in a direction away from the front surfaceof the body, wherein the one or more positioning lips arecircumferential around a center point of the one or more valves, andwherein the one or more positioning lips form a receiving recess toassist with applying even pressure to the valve to deform the valve. 21.The gasket of claim 20, wherein the one or more positioning lips are twopositioning lips that each include a receiving surface defining thereceiving recess.
 22. The gasket of claim 21, wherein the receivingsurfaces are generally parallel with each other.
 23. The gasket of claim21, wherein the receiving surfaces are either convex or concave aboutthe receiving recess.
 24. The gasket of claim 21, wherein the receivingsurfaces are asymmetrical about the center point of the one or morevalves.